What is a "fistulated cow"?

A student reaches into the stomach of a fistulated cow. The cow is perfectly health and the fistula can be closed using a plug.It is hard to get a look inside a living cow, so sometimes animal scientists created fistulated cows. A fistulated cow is a cow with a fistula (or passageway) connecting the cow's stomach with the outside.

A fistulated cow has an opening cut into her stomach. The opening has a ring around it, and it can be closed with a big plug. The cow heals around the ring, and the cow continues to digest food as if the opening wasn't there.

By creating this window into the cow's stomach, scientists can learn how the stomach works. They can see how fast a cow can digest certain foods. They can also learn about the bacteria that live in a cow's stomach. 

Reaching into a cow's stomach is a very strange feeling. The cow is working hard to break down feed, so the stomach is very warm because of this energy. The fistula opens in a part of the stomach called the rumen. The sides of the rumen feel soft.

A fistulated cow can also be called a cannulated cow. Learn more about cattle